The present invention relates to sealing of a bearing, and more particularly, to a sealing plate for a bearing, and a method of manufacturing thereof.
In a conventional sealing plate 56 for a bearing shown in FIG. 26, a core metal formed by punching a metallic plate is placed in a recess or concave portion of a metal mold for molding. Then, elastic material is poured in the mold, subsequently heated and pressurized, simultaneously vulcanized, and thus the bearing sealing plate is formed. The forward edge diameter of the formed sealing plate 56 is larger than an opening diameter of a bearing sealing groove 51a, and a wall face of the sealing groove of an outer ring 51 or inner ring 52 of the bearing is sunken so as to force the bearing sealing plate 56 into the sealing groove 51a, thus causing the elastic forward edge portion of the sealing plate 56 to depress the wall face of the sealing groove 51a to achieve the sealing. In FIG. 26, reference numeral 50 denotes a ball of the bearing, 53 a retainer, 54 the core metal of the sealing plate 56, and 55 a ring-plate made of elastic material such as synthetic rubber and having a lip 55a sliding on a tapered face 52a of the inner ring 52.
In the conventional manufacturing method of the bearing sealing plate as described above, however, there have been such disadvantages that, not only the metal mold is necessary, but a lot of expense is required for the metal mold due to complicated construction and shapes between the bearing sealing plate and the sealing groove of the bearing. Also, a considerable amount of time is required for the vulcanization of rubber with the mold, and removal of burr from the bearing sealing plate is also required after the molding. This results in an increase of the number of manufacturing steps and time, with a consequential rise in cost.